The invention relates to an improvement in a device for forming peices of finned heat transfer tubes and thereafter delivering the finned tubes to a coil winder device.
In order to appreciate more fully the inventive advance of the present invention over the prior art systems, consideration is to be given to a number of related devices over which the present invention is an improvement.
The U.S. Pat. No. 2,865,424 to McElroy for a Machine for Forming Finned Heat Transfer Tubes, teaches a device which can be employed for forming finned heat transfer tubes. A primary object of this reference is to provide cooperating means for simultaneously moving a tube axially while rotating about its axis, the rotation of the tube affecting the wrapping of fin strip stock on the tube, and for deforming the strip as it is coiled on edge about the tube, to insure the creation of a smooth spiral fin which has its inner peripheral edge in proper heat transfer association with the exterior surface of the tube. During wrapping, the tube is merely delivered through a rotatable support which supports the fin portion of the tube to eliminate wear on the fins as the tube is being rotated for wrapping. The McElroy patent does not appear to be concerned with the handling of the tube once it exits the wrapping device.
The U.S. Pat. No. 2,780,268 to Edwards teaches an apparatus for making lipped finned tubing. In this device, after the fins have been secured to the conduit, the assembled finned tubing is delivered to an oven and thereafter to a ledge to be cut into size and finally delivered to a supporting table for packing.
In a U.S. Pat. No. 3,796,389 to Nishiyeri et al, a system is described for winding strips of material into rolls, wherein alternate mandrels are driven by a clutching mechanism which allows changing the mandrel being driven. The clutch means is capable of bringing the power transmitting output shaft into and out of engagement with the driven shafts or mandrels. While the strips of the band plates are being wound by one of the driven shafts which is in driving engagement with the driving means, the other of the driven shafts is held stationary, that is, comes out of engagement with the driving means so that the coils therearound, if any, can be bound up with a suitable strap and thereafter separated therefrom during the winding of the band plates by one of the driven shafts. This patent contemplates the use of a clutching mechanism capable of engaging one of several shafts to drive the shaft whereby thin band plates may be wound about the shaft. The present invention is concerned with an improved machine or device for forming finned heat transfer tubes and is not concerned with various clutching mechanisms for alternately driving shafts for winding thin band plates into rolls. The Nishiyeri et al patent is cited as an example of a prior art winding apparatus, in general.
Several additional patents which are of interest in showing the prior art are Bundy U.S. Pat. No. 1,720,508; Bishop et al U.S. Pat. No. 2,702,166; Nihlen U.S. Pat. No. 3,568,288; and Boose U.S. Pat. No. 3,652,820.
The Bundy patent is directed to the formation of tubing from flat stock, followed by the soldering of fin material to the tubing. No description of a system, according to the instant invention as will be described below, is shown in this patent.
In Bishop et al, a fin is wrapped about a piece of already formed tubing, the machine automatically stopping when wrapping has been completed for removal of the tube from the machine.
Nihlen shows the grooving of a tube to accommodate a thin strip and the forcing of a thin strip into that groove while expanding portions of it. Similarly, in Boose, an L-shaped fin is helically wound onto a tube and welded into place.